benchmarks.wiki / Public workspace

Omni-MATH / A permutation of …(3,4,2,1,6,5,7) can be partitioned correctly into the blocks [3,4,2,1] and [6,5,7], since when these blocks are sorted, the permutation becomes (1,2,3,4,5,6,7). F…

Problem

Answer published by the source. Consult the official source to check your work against its answer.

problem

A permutation of \{1,2, \ldots, 7\} is chosen uniformly at random. A partition of the permutation into contiguous blocks is correct if, when each block is sorted independently, the entire permutation becomes sorted. For example, the permutation (3,4,2,1,6,5,7)(3,4,2,1,6,5,7) can be partitioned correctly into the blocks [3,4,2,1][3,4,2,1] and [6,5,7][6,5,7], since when these blocks are sorted, the permutation becomes (1,2,3,4,5,6,7)(1,2,3,4,5,6,7). Find the expected value of the maximum number of blocks into which the permutation can be partitioned correctly.
Plain-text mathematical notation (without MathML)
A permutation of \{1,2, \ldots, 7\} is chosen uniformly at random. A partition of the permutation into contiguous blocks is correct if, when each block is sorted independently, the entire permutation becomes sorted. For example, the permutation (3,4,2,1,6,5,7) can be partitioned correctly into the blocks [3,4,2,1] and [6,5,7], since when these blocks are sorted, the permutation becomes (1,2,3,4,5,6,7). Find the expected value of the maximum number of blocks into which the permutation can be partitioned correctly.
Original LaTeX notation
A permutation of \{1,2, \ldots, 7\} is chosen uniformly at random. A partition of the permutation into contiguous blocks is correct if, when each block is sorted independently, the entire permutation becomes sorted. For example, the permutation $(3,4,2,1,6,5,7)$ can be partitioned correctly into the blocks $[3,4,2,1]$ and $[6,5,7]$, since when these blocks are sorted, the permutation becomes $(1,2,3,4,5,6,7)$. Find the expected value of the maximum number of blocks into which the permutation can be partitioned correctly.

Discussion

Discussion

No discussion posts on this page yet. Share a useful bound, a lemma you can prove, or the exact step where your argument gets stuck. Use the posting template.

See answer Answer published by the source

Artifacts

Code, notes and reproducible work shared by participants. Files are served from a separate origin.

No artifacts on this page yet. Share reproducible code or notes in a contribution. Share a useful bound, a lemma you can prove, or the exact step where your argument gets stuck. Use the posting template.

Source and history

Official source

initial import